FyroxEngine/Fyrox · warning

Window width was

Error message

Window width was {}

What it means

When a root-level Window is made visible it checks its dimensions. If the width is non-finite (NaN or infinity) the window would render incorrectly, so it is logged and forcibly reset to 200.0 pixels.

Solutions

1. Set a finite explicit width in WindowBuilder: `.with_width(400.0)`
2. Validate window geometry loaded from config/user settings before applying (reject NaN/inf)
3. Find the source of the NaN/inf in your size computation (division by zero, uninitialized f32)
4. Rely on the library fallback only as a stopgap — it clamps to 200.0 which may not be desired

Example fix

// before
let width = saved_size[0] / scale_factor; // may be NaN
WindowBuilder::new(...).with_width(width)
// after
let width = saved_size[0] / scale_factor;
let width = if width.is_finite() { width } else { 400.0 };
WindowBuilder::new(...).with_width(width)

fn finite_dim(v: f32, fallback: f32) -> f32 {
    if v.is_finite() { v } else { fallback }
}
let width = finite_dim(config.width, 400.0);

fn is_finite_size(w: f32, h: f32) -> bool { w.is_finite() && h.is_finite() }

When it happens

Trigger: Showing a Window (`WidgetMessage::Visibility(true)`) whose width is NaN/inf — e.g. WindowBuilder given non-finite desired width, or width computed from invalid layout math; only applies when the window is a child of the UI root.

Common situations: Passing computed sizes (from division by zero or uninitialized variables) into WindowBuilder; loading window geometry from corrupted config files containing NaN; forgetting to set an initial width.

Understand the failure class

Background: "Must be a positive integer", "Invalid value", "Unsupported": the invalid-argument-value error family, when a library rejects the value you pass — this error's family across 35 libraries.

Related errors

• Window height was
• Node row out of bounds
• Node column out of bounds
• Cannot add window to split tile
• Cannot subtract window from split tile

AI-assisted analysis of FyroxEngine/Fyrox@76c91aad8e (2026-09-10). Data as JSON: /api/errors/d0823c800fd4a083. Report an issue: GitHub.

Appendix: source

Thrown at fyrox-ui/src/window.rs:584

            } else if message.destination() == self.close_button {
                ui.send(self.handle(), WindowMessage::Close);
            }
        } else if let Some(msg) = message.data_for::<WindowMessage>(self.handle()) {
            match msg {
                &WindowMessage::Open {
                    alignment,
                    modal,
                    focus_content,
                } => {
                    // Only manage this window's visibility if it is at the root.
                    // Otherwise, it is part of something like a tile, and that parent should decide
                    // whether the window is visible.
                    if !self.visibility() && self.parent() == ui.root() {
                        ui.send(self.handle(), WidgetMessage::Visibility(true));
                        // If we are opening the window with non-finite width and height, something
                        // has gone wrong, so correct it.
                        if !self.width().is_finite() {
                            Log::err(format!("Window width was {}", self.width()));
                            self.set_width(200.0);
                        }
                        if !self.height().is_finite() {
                            Log::err(format!("Window height was {}", self.height()));
                            self.set_height(200.0);
                        }
                    }
                    ui.send(self.handle(), WidgetMessage::Topmost);
                    if focus_content {
                        ui.send(self.content_to_focus(), WidgetMessage::Focus);
                    }
                    if modal && !ui.restricts_picking(self.handle()) {
                        ui.push_picking_restriction(RestrictionEntry {
                            handle: self.handle(),
                            stop: true,
                        });
                    }
                    match alignment {

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